pushCurrentStateToUndoStack method
void
pushCurrentStateToUndoStack()
REMEMBERS CURRENT CANVAS STATE IN UNDO STACK
Implementation
void pushCurrentStateToUndoStack() {
_latestActions.add(<Point>[...points]);
//CLEAR ANY UNDO-ED ACTIONS. IF USER UNDO-ED ANYTHING HE ALREADY MADE
// ANOTHER CHANGE AND LEFT THAT OLD PATH.
_revertedActions.clear();
}